From 1dfb086ca8220bee3ad978ac64df0c988853aa44 Mon Sep 17 00:00:00 2001
From: Alessandro Astone <ales.astone@gmail.com>
Date: Tue, 16 Feb 2021 20:03:54 +0100
Subject: updater: Do not null terminate mount_flags_list array

mount_flags_list is a c-style NULL terminated array, but when
iterating over it via
    for (const auto& [name, value] : mount_flags_list)
the last { 0, 0 } is considered a valid entry.
Then `name` is NULL but checked with (flag == name),
which causes SIGSEGV.

Also move the definition to within setMountFlag()
and make it an std::pair array

Change-Id: Ia6670113620c6e8f95151fda764c3ab40bc2d67e
---
 updater/updater_runtime.cpp | 40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/updater/updater_runtime.cpp b/updater/updater_runtime.cpp
index e93830505..bac078cf9 100644
--- a/updater/updater_runtime.cpp
+++ b/updater/updater_runtime.cpp
@@ -44,29 +44,25 @@ std::string UpdaterRuntime::FindBlockDeviceName(const std::string_view name) con
   return std::string(name);
 }
 
-static struct {
-  const char* name;
-  unsigned flag;
-} mount_flags_list[] = {
-  { "noatime", MS_NOATIME },
-  { "noexec", MS_NOEXEC },
-  { "nosuid", MS_NOSUID },
-  { "nodev", MS_NODEV },
-  { "nodiratime", MS_NODIRATIME },
-  { "ro", MS_RDONLY },
-  { "rw", 0 },
-  { "remount", MS_REMOUNT },
-  { "bind", MS_BIND },
-  { "rec", MS_REC },
-  { "unbindable", MS_UNBINDABLE },
-  { "private", MS_PRIVATE },
-  { "slave", MS_SLAVE },
-  { "shared", MS_SHARED },
-  { "defaults", 0 },
-  { 0, 0 },
-};
-
 static bool setMountFlag(const std::string& flag, unsigned* mount_flags) {
+  static constexpr std::pair<const char*, unsigned> mount_flags_list[] = {
+    { "noatime", MS_NOATIME },
+    { "noexec", MS_NOEXEC },
+    { "nosuid", MS_NOSUID },
+    { "nodev", MS_NODEV },
+    { "nodiratime", MS_NODIRATIME },
+    { "ro", MS_RDONLY },
+    { "rw", 0 },
+    { "remount", MS_REMOUNT },
+    { "bind", MS_BIND },
+    { "rec", MS_REC },
+    { "unbindable", MS_UNBINDABLE },
+    { "private", MS_PRIVATE },
+    { "slave", MS_SLAVE },
+    { "shared", MS_SHARED },
+    { "defaults", 0 },
+  };
+
   for (const auto& [name, value] : mount_flags_list) {
     if (flag == name) {
       *mount_flags |= value;
-- 
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